Same view as in previous image, but about 20 seconds later. Now lav...

Same view as in previous image, but about 20 seconds later. Now lava is now falling into the fissure, destroying sheets of crust in the process. When the draining was over, lava level had dropped about 50 m (160 ft). Once draining was complete, lava level again began to slowly rise as it was pushed upward by expanding gas bubbles. Gas pistoning is common in lava ponds and lakes that are continuously supplied with gas.